Kevin Schroeder has posted a step-by-step guide to his site today about creating a module for Magento in the first of a series of posts about Magento.

I believe that one of the best ways to learn something is to write out what it is you are learning. This forces you to think through the concepts and determine how to explain them to others. In doing so you are forced to use terms that are familiar to describe this new thing. This helps to solidify the concepts in your own mind, making it easier to remember. But still, there are three caveats: Magento 2 is not out yet, I'm learning as I write and what I share is what I see (my interpretation).

He talks about some of the differences between Magento 1 and 2 including:

The lack of code pools

Discovery XML files are in a different location

A different parser for these XML files

With all of this configuration and location information covered, he gets into the actual module building. He makes a simple "Hello World" module with a module.xml, event.xml and an Observer that handles sending the text back to the waiting application.